Traditional and contemporary Japanese architecture is examined, with focus on the characteristics of emptiness and changeability, the point of departure being Japanese conceptions of space which are interpreted and described from a Western perspective. According to Japanese cultural tradition space is conceived as a subjective perception, a physical experience and a changeable process. A description and analysis of how these conceptions of space are expressed and perceived in architectonic forms, both in traditional sukiya architecture and in a selection of contemporary works of architecture, is then presented. The buildings discussed in the thesis are, among others, the Katsura villa, the pavilions Rinun-tei and Kyusui-ken in Shugaku-in, Shisen-do, Hillside Terrace, Church with the Light, Villa in Shimo-gamo, Gifu Kitagata Apartment Building and Tofu. The contemporary works of architecture have been designed by Fumihiko Maki, Tadao Ando, Waro Kishi, Kazuyo Sejima and Jun Tamaki. Besides visiting the buildings, articles written by these architects have been studied which convey their views on architecture. These texts reflect both Japanese and Western influences in a global debate about architecture. This thesis is based on a direct experience of various buildings together with a personal Western interpretation. In this way the subjective experience is put into focus and leads to a discussion about architecture based on concepts or perceptions. The strong Japanese architectural tradition lives on in the reinterpretations of contemporary architecture, the study of which creates a deeper understanding of the tradition. In this foreign world of architecture there is room for dimensions which could become an architectonic challenge in designing new buildings and environment.